title: Allogenous bone with collagen for repair of deep osteochondral defects.
abstract: BACKGROUND
  A scaffold for treatment of deep osteochondral defects should be stable, integrate well, and provide a surface for chondrocytes. To meet these demands, a biphasic scaffold of allogenous sterilized bone with a collagen surface was developed. Integration was tested in the sheep model.
  
  
  METHODS
  Cartilage chips were taken from the nonweight-bearing area of the left knee of 12 sheep and cultured. After 4 wk a second procedure followed and defects of 9.4-mm diameter at the weight-bearing area of the medial femoral condyle of the right knee were created. The sterilized scaffold was inserted and the cultured autologous chondrocytes were dripped onto the surface. After 6 wk, 3 mo, and 6 mo the animals were sacrificed; the explanted femoral condyles were evaluated macroscopically and using histologic, immunohistochemical, and electronmicroscopic methods.
  
  
  RESULTS
  After 6 wk the level of the surface was well preserved, after 3 mo parts of the scaffold were sintered but after 6 mo the surface was continuous. Full integration of the allogenous bone could be observed after 6 mo. The surface of the scaffold after 6 wk consisted of bone, but after 3 mo some chondrocytes and after 6 mo a continuous chondral layer could be detected.
  
  
  CONCLUSIONS
  The biphasic scaffold of allogenous bone and collagen proved to be stable and sufficiently integrated in the short- and midterm interval. Whether the chondrocytes on the surface had been derived from implanted chondrocytes or the scaffold with its surface was sufficiently chondroconductive must be answered in further investigations.
authors.affiliation: Department of Trauma Surgery Giessen, University Hospital of Giessen-Marburg, Justus-Liebig-University Giessen, Giessen, Germany. Electronic address: iris.schleicher@ortho.med.uni-giessen.de.
authors.forename: Iris
authors.initials: I
authors.lastname: Schleicher
authors.forename: Katrin S
authors.initials: KS
authors.lastname: Lips
authors.forename: Ursula
authors.initials: U
authors.lastname: Sommer
authors.forename: Ines
authors.initials: I
authors.lastname: Schappat
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Martin
authors.forename: Gabor
authors.initials: G
authors.lastname: Szalay
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schnettler
mesh_terms: D000818:Animals; D016025:Bone Transplantation / Q000379:methods*; D002358:Cartilage, Articular / Q000502:physiology*; D019902:Chondrocytes / Q000166:cytology / Q000502:physiology; D003094:Collagen / Q000494:pharmacology*; D004195:Disease Models, Animal; D005260:Female; D005269:Femur / Q000473:pathology / Q000601:surgery*; D055034:Osteochondrosis / Q000473:pathology / Q000601:surgery*; D012038:Regeneration; D012756:Sheep; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D014184:Transplantation, Homologous
chemical_list: D003094:Collagen
keywords: Allogenous bone; Autologous chondrocytes; Biphasic scaffold; Cartilage regeneration; Osseous integration; Osteochondral defect